https://bugs.squid-cache.org/show_bug.cgi?id=5009

--- src/acl/Options.cc.orig	2019-11-06 06:14:40.000000000 +1100
+++ src/acl/Options.cc	2019-11-18 20:57:12.000000000 +1100
@@ -246,14 +246,14 @@ Acl::ParseFlags(const Options &options, 
 const Acl::Options &
 Acl::NoOptions()
 {
-    static const Options none = {};
+    static const Options none{};
     return none;
 }
 
 const Acl::ParameterFlags &
 Acl::NoFlags()
 {
-    static const ParameterFlags none = {};
+    static const ParameterFlags none{};
     return none;
 }